Aplectana tucumanensis n. sp., from the large intestine of Amphisbaena bolivica, is described and illustrated. Of the 43 nominal species of Aplectana, A. tucumanensis n. sp. represents the fourth species reported in Amphisbaena spp. These 4 species are separated on the basis of male characters: spicules of Aplectana alba approximately 60 μ in length, Aplectana pusilla and A. tucumanensis approximately 100 μ, Aplectana raillieti greater than 230 μ; papillae pattern of A. pusilla with 3 preanal pairs, 2 adanal pairs, 6 postanal pairs, and 1 median papilla compared to 9 preanal pairs, 1 adanal pair, 6 postanal, and no median papilla for A. tucumanensis.